Method of making a stiffened permeable resin coated fibrous sheet



July 15 1952 A. F. scHRAMM, JR 2,503,575

METHOD OF MAKING A STIFFENED PERMEABLE RESIN COATED FIBROUS SHEET Filed Nov. 17, 1949 47 TOR/VE Y Patented July 15, i952 A UNITED STATES PATENT] oFFlcl:

METHOD F MAKING A STIFFENED PERME- ABLE RESIN COATED FIBROUS SHEET August F. Schramm, Jr., white Plains, N. Y. Application-November 17, 1949, Serial No. 127,910

This invention relates lto a treatedsheet yand the methodof making it.,

` vThe invention is particularly useful in connection lwith the treatment of textile fabricsl and productfthe particles of stiffening material penetrate the'fabric at closely spaced positions and leave permeable spots between the positions of the particles of stiiening material.

Themethod and `product of this earlier application are useful. A disadvantage arises when the treatment is applied to a dyed fabric or to onei that has fbeen made water repellent. The solventthere introduced has the property of disturbing the distribution of the dye and the added water repellent. Thus the addition of the dust ofthe plastic over the surface of the plasticizermoistened fabric, warming, and pressing in the dust at spaced positions, as described in the earlier application, results in some instancesv in spotting ofthe color andalso loss of water repellency of the'previously treated fabric.

lI have nowdiscovered a method and product in-Which theloss of water repellency is prevented and spotting of one side lor face of the fabric is prevented. Y

` Brieiiy stated, my invention comprises moistening the permeable sheet with a volatile nonsolvent for the plastic material to be applied as .stiffenenA applying the plastic material in the former solid spaced particles, onthe moistened sheet, anchoring the particles so applied, and evaporating the non-solvent liquid.

The result of this treatment is the penetration of the particles of plastic material into one side only and adjacent parts of the sheet directly below that side. Because the non-solvent acts as a barrier, the penetration doesnot extend all the way through the sheet. The face opposite that to which the plastic material is 'applied is notspotted or mottled in color. Neither is the Watenrepellent material of the opposite face extractedand concentrated in the spaced particles of plastic material. The product remains per-'- meable to perspiration, air and moisture and possesses what is usually referred to as lbreathing properties. I*

The plastic material applied to one side of the sheet as described may be Aused as the binder for laminating two or more sheets which are brought together with the treated face insidethe assembly.j Inthe lamination, the plastic binder is concentrated where it will do the most good,- on the side being adhered to another layer of fabric. The yin vention will be illustrated in greater detail in connection with the drawingsto which reference is made. `VFig'. l1 is a sidel view partlyin section of ap'- pa'ratus for treatingV a sheet in accordance with the invention.

v Fig. 2 is an enlarged plan view, partly broken away for clearness `of illustration, of a iinished treated fabric. s'

s Fig. 3 is a sectional view on line 3--3 ofz Fig. 2.

Fig. 4 is.l a sectional view of a laminated product made inv accordance with the invention.

Fig. y is a like view of another laminated product, and

Fig. 6 is a sectional view on an enlargedscale showing the condition of the sheet materialbefore removal f those of theparticles of applied plastic that are not'in direct contact with the There are shown the sheet material I0 to be treated, container l2 for water or like non-solvent material I4, filling funnel I6, pick-up roller I8, land'doctor blade 20 for forming and directing a sprayk22 against the sheet material Ill.v The sheet material passes over guide rollers 24, 26 and 28 and is finally rolled up on the reel 30. The particles of plastic material 32 which are to'be applied to the sheet material are maintained in a suitable container 34 with conveyor 36 delivering material from the container to charging chute 38 and then to the spreading box 40I from which a layer 42 `of the plastic material is spread upon the conveyor 44.

This conveyor passes over the rollers 46 and 48 one of which is driven by conventional drive means that are not shown. The direction of the reach of the conveyor carrying theplastic material is counter to the direction of movement of the sheet material Il).V The sheet material to be treated, in moving counter to the direction of the conveyor 44, passes under the pressure member 5| which holds the sheet material under light pressure against the layer 42 of plastic material,- so that the plastic lmaterial isrubbed onto the cloth.

A conventional typeof vibrator 52 contacts the untreated sideorop 0f the cloth as the cloth leaves the pressurev member 5| and passes up-V the adhered layer of plastic particles passeslv through a bank of infrared lamps 58, serving 'as-.a f heater and then through a coolingfchambersuch.

as one containing the spaced blowers.

The cloth so processed is ready for use, .as in f making shoes. v .In one use, the treated cloth's laminated with another sheet or other sheets, to makeplied products such as illustrated in Figs. 4 and 5.

,Here the plastic materialis onV the inside.

It serves as a binder to holdthe sheetstogether after` theyhave been hot-rolled orironed andrthen.v allovvedtocoolpm. l

These. plied .products are permeable, -as .shown .for instance by the arrows of Figs. 4j and 5.V c

Theoperation of theapparatus will 13e-largely yevident from the description of it that has been given. `In brief, the particles of'solid material are applied by moving a layerof them counter tothe direction ofmovement of and against the sheetmaterial to beftreated. The sheet material at this time is pressed by slight pressureagainst .the.upper surface of. the. layer, so that there is rubbing of the partiolesonto oneside .of the sheet. Then as the sheet is separated fromthe Aremaining ymass lof particles and preferably movedzup- Wardly, the sheetis tapped slightly Vupon Athe side opposite the. adhered particles.l As a result particles that. are not indirect contact with the vsheet fall from'the sheet. The result is a mosaic of .spaced particles or islands ofthe dust of plastic material.' f This sheet with the applied spaced .particles .of `plastic isthen subjected to treatment .to anchor the particles in position on one side of the sheet. The warming causes evaporationof the volatile non-solvent material originally usedr and also softening ofthe particles of thermoplastic to the stageat whichv they are drawn into the. sheet by capillarityas the content of volatilenon-solvent is reduced.` The particles, howevendo not come to extend .completely through the sheet. This `anchoring of the particles. to the vsheetzmay be taccelerated by the application of. pressure by ,conlventional .ironing or rolling means, that is, calfendering (not shown), to the warmed vsheet during 'theevaporation of the solvent.

A k'During the application of the-plastic dust to the lower side of the sheet .fabric as shownin 'the drawing, the other'sidey is protectedfto advantage -from settling of dustuponit, as byvan overriding beltof usual kind v(not shown). i f e The .original moistening of the sheet material ,to be treated is eectedby any convenient means and with. conventional .equipment suchaspassing the sheet through a bath of the selected solvent andsubsequent. squeezing out of the. excess. between rollers, this equip-ment being conventional. lluse-to advantage spray equipment to .apply the non-solvent to the sheet. 'The proportion of water or other non-solvent at the time the dustis applied is somewhat less thanthe saturationprportion.r The proportion of .non-solventapplied mustbe adequate towet all thebers on theside 4 of the sheet to be treated. As a result, there are no dry spotsI into which the plastic material as applied may penetrate without restriction.

Theheating of the sheet material and applied plastic dust is effected to advantage in a usual type of infrared heating equipment. The time of 15 sec. to 1 min. or so in the hot zone is adequate to eifect the drying. The non-solvent evaporates. evenly and non-violently. *A tem- -peraturefnear the sheetmaterial of approximately 290 to 350 F. is satisfactory. I have used to advantage a temperature of about 300 and a time of heating inthe. infrared heating Zone of 15 sec. While a textile fabric such as one of cotton,

wool, rayon or nylon ispreferred as the base material, 'I'mayfuse other fibrous sheet material as,

. forinstance, paper, cardboard, or thin felt.

As the plastic there is used one which is stable, solid. at ordinary temperatures, and subject to hardening after impregnation into the surface .portions-` of the sheetmaterial. yWhen thehvanchoring of the plastic within-.thesheet material isto loe-effected by Warmingfand subsequent cooling from the-lieatsof.tenedcondition, theplastic shouldbef/one thatl is thermoplastic; When the non-solventused is Water, the plastic should. .be water insoluble both beforeand aftercompounding with the plasticizer. Examples of plastics thatr may .be used are .a vinyl chloride resin .such as the copolymer ofvinyl chlorideandvinylace-g tate -in the proportionr of..about' .l5f parts of the former to 5 of the lattenpolyvinylbutyral, cellulose acetate, and methyl methacrylate. y

Thefplastic material selected is suitably plasticized `with one oftheknovvncommercialplasticizersrffor the particular plastic selected. The plasticizer should lbe non-toxic. under conditions ofY .use .and Vpreferably also. non-flammable.. `Examples osuch plasticizers that may be used are tributyoxyethyl phosphate, dimethoxyethyl phthalate, van alkyl aryl phosphatesuch asbutylcresyl phosphate or Santicizer 1.417, and vtricresyl phosphate.V When the plastic'material .used .is cellulose acetate, Il prefer to. use the'dimethoi'rye ,ethyl phthalate.. Y 4., *In place. ofwatenthelfe kmay. be usectas` the non-solvent, .cleaners.naphtha, lto'luol', alcohol, .or the like. .Knownsolubilities offthe plasticized materi'aLwill control the selection of the nonsolvent, toensure the desired non-solvent.proper-f ties...

Asto proportions, the plasticizer is used inthe amount of about25 to 125 parts for 100 parts of the plastic of the kind described. The amount of plasticizer used must be adequate to give softening ofthe `plastic material when warmed to. about 200 F. but must be below .the amountwhich, if used, would cause the solid particles of plastic material to coalesce -in contact with. each,l other at normal temperatures. The proportion ofthe plastic material islsuch that the plasticized'pa'rticles or plastic material .willflow over themselves, during the application by rubbing onto the sheetvmaterial inthe manner described above. In other Words, the particles of the plasticmaterial-.are free ilowing and non-coherent; the combination of the plastic and thei plasticizer being herein referred to for convenience as plastic material.

In the finished product'. itis -considered that theA closely spaced masses of plasticV material cover about 1A; to 3A of the area on the one -side of the sheet material.vv The masses Y,contact at certain points toY give. a skeletonized structure.

The invention will be further illustrated by detailed description in' connection with the foly f lowing specific examples.

Ewample 1"# Woven l' cotton fabric' such as V'used 4 in canvas shoes, is passed through the zone of a water have been rubbed together-overa distance of a foot or so, the fabric withparticles of the plastic "dust adhering to one side is thenv drawn upwardly in, inclined position, with the particle-ooatedgsvide v'down'.f Dlll'ng thisrdrawingsof the faibIQ; the -fabric isftapped lightly on .thegbaok (upper side) tov cause Adislodgmentgof particles of the plastic dust other than those that are in direct contact with the moistened cloth. When this has been done, then the cloth with remaining particles of the dust still adhering to the cloth is passed through an infrared heating zone. This softens the plastic material. The softened material sinks into the surface portions of the cloth without passing completely through the cloth. During this heating operation, the moisture in the cloth is evaporated.

The plastic material used in this example is the polyvinylchloracetate plastic VYNW containing 80 parts of the tributoxyethyl phosphate as plasticizer for 100 parts of the polyvinyl resin. Such a product is made by spray drying a solu- 'smokecanbe blown through :the sheet. The' application ofthe dust to one side of the .sheet doesnot affect the appearance of the other side but doesgive to the whole sheet the desired-stiffening effect. f .1-51

' The'particles of .plastic material that farefused mayf containconvent'ional ingredients: Thus,

v they may contain stabilizers, inert fillers,l or 'coltion of the plastic and atomizing plasticizer against the resulting solid particles while they are still suspended in the drying chamber.

The procedure of Example 1 is repeated except that, in place of the phosphate plasticizer there described, there is used an equal Weight of the Santicizer 141.

Emample 3 The procedure of Example 1 is followed except that, in place of the phosphate there described, there is used an equal weight of tricresyl phosphate and, in another preparation, an equal weight of dimethoxyethyl phthalate.

Example 4 The treated sheet materials made as described in Examples 1-3 is subjected to a hot ironing operation. The applied particles of dust are thus anchored more deeply in the fabric by pressure applied to them at the time they are in heatsoftened condition.

Example 5 Example 6 i The procedure of Examples 1-4 was followed except that the fabric Was replaced by a rather thick paper of sulfite pulp and, in another run, by thin felt.

Products made as described still retain their penetrability to moisture and air. A drop of water placed on one side of the thus treated fabric passes through at once to the other side. Also oring substances.

, lThe particles of plastic V'material may-be 'apjplied to both faces of the sheetmaterial.t For this purpose the same .treatmentisgiventothe second facev that has been appliedas described to the first face. Sheets that have beenl treated on both faces areparticularly usefulfaslthe lami- Y-nating sheetinvplying togethertwo other sheets, as in the making of a collar stock'. `i r f When the plastic material is given: the desired coloras by the incorporation of pigments-or' dyes, then` the effect on the treatedfacemay be one that is desirable in appearanceforcertainuses. In other words, my .niethodand product provide a fabric or like sheet material with a new form of appearance of surface.

Also, the face of the sheet material that has been treated as described may be subjected to conventional embossing operations. In these operations the plastic material comes to be embossed in pattern desired.

The omission of pretreatment of the sheet material with organic solvent for the plastic used .is a matter of great economy in the operation. It is also advantageous in the reduced penetration which is obtained in the absence of the organic solvent. As a result the treated sheet material, when a fabric, retains a large proportion of its permeability and breathing properties although the percentage of open meshes or spaces in the over-all product is reduced from that which characterized the original sheet material. This retention of a part only of the permeability is desirable in certain uses, as, for instance, in shoe stock, where the original free permeability to Water is objectionable.

When it is desired to increase the proportion of plastic material applied or to increase the thickness of the spaced islands of the plastic material in the finished product, the treatment described may be repeated. In this way the particles come to build up one on another.

Also the particles applied as described may be somewhat elongated, as in the form of flock of thermoplastic material. When this is the condition, then a pile-type of finish is obtained on the fabric.

It will be understood also that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of the invention'.

What I claim is:

1. In making a sheet that contains applied plastic and is permeable to air and moisture, the method which comprises moistening with water a permeable fibrous sheet provided with ne pore spaces and being non-softening and nondeteriorating at the softening temperature for the said plastic, applying over the moistened sheet a layer of non-coherent free flowing solid particles of a water insoluble organic thermoplastic material and of size about 20 to 200 mesh, removing the applied material except for a single layer of spaced particles thereof directly in contact With the moistened sheet, and then thermoplastic material Vis softened, to cause adherence thereof within the surface portion'of v,the

f'sheehthe Water in the Pmostened sheet as 'used decreasing the penetration of theplastcfma- Vterial on the sheet.

2. The method of claim l, infwhich calender 4pressure isV applied during the step vofwaiming Ythe treated sheet.r I x 113.1 ,'Iheyrnethod' of claim -1 in which 'the said applying of theparticlestothe moistened-sheet is.- eiected by contactingV a loose klayer of the .saiclparticlesy with the lower faceof the mostened sheet, causing movement ofthe layer ofv particles in one direction and fofthe' sheet-in the .opposite direction, and. maintaining contact of therparticles Vand sheet during the. said movement.. S10 "that the particles are rubbed against theflowenfacelof "the moistened sheet.,= Y

AUGUST. F. .'SCHRAMMI, J R;

REFERENCES `CI'IED The following references are of'record 'in the le of this patent:

UNITED STATES PATENTS 

1. IN MAKING A SHEET THAT CONTAINS APPLIED PLASTIC AND IS PERMEABLE TO AIR AND MOISTURE, THE METHOD WHICH COMPRISES MOISTENING WITH WATER A PERMEABLE FIBROUS SHEET PROVIDED WITH FINE PORE SPACES AND BEING NON-SOFTENING AND NONDETERIORATING AT THE SOFTENING TEMPERATURE FOR THE SAID PLASTIC, APPLYING OVER THE MOISTENED SHEET A LAYER OF NON-COHERENT FREE FLOWING SOLID PARTICLES OF A WATER INSOLUBLE ORGANIC THERMOPLASTIC MATERIAL AND OF SIZE ABOUT 20 TO 200 MESH, REMOVING THE APPLIED MATERIAL EXCEPT FOR A SINGLE LAYER OF SPACED PARTICLES THEREOF DIRECTLY IN CONTACT WITH THE MOISTENED SHEET, AND THEN WARMING THE THUS TREATED SHEET TO A TEMPERATURE OF AT LEAST 200* F., TO CAUSE EVAPORATION OF WATER, AND CONTINUING THE WARMING UNTIL THE THERMOPLASTIC MATERIAL IS SOFTENED, TO CAUSE ADHERENCE THEREOF WITHIN THE SURFACE PORTION OF THE SHEET, THE WATER IN THE MOISTENED SHEET AS USED DECREASING THE PENETRATION OF THE PLASTIC MATERIAL ON THE SHEET. 